Organochlorine insecticide residues in drinking and ground water in and around Delhi

A multiresidue method was developed for the estimation of 15organochlorine pesticides in water. 50 samples of drinking watersupplied by the Municipal Corporation to the residential areasof Delhi and 20 ground water samples from nearby villages usedfor irrigation were monitored for the presence of organochlorineinsecticides by the method developed. Although, organochlorinepesticides were detected in the ground water and irrigationwater samples, the levels of pesticides were below the MaximumContaminant Level as prescribed by WHO. No organochlorineinsecticides were detected in any of the drinking water samples.     

Silver nanoparticles tolerant bacteria from sewage environment

Silver nanoparticle (SNP) is a threat to soil, water and human health. Protection of environment from silver nanoparticles is a major concern. A sewage isolate, Bacillus pumilus treated with SNPs showed similar growth kinetics to that without nanoparticles. A reduction in the amount of exopolysaccharides was observed after SNPs – B. pumilus culture supernatant interaction. The Fourier transform infrared spectroscopy (FT-IR) peaks for the exopolysaccharides extracted from the bacterial culture supernatant and the interacted SNPs were almost similar. The exopolysaccharide capping of the SNPs was confirmed by UV-Visible, FT-IR and X-ray di raction analysis. The study of bacterial exopolysaccharides capped SNPs with E. coli, S. aureus and M. luteus showed less toxicity compared to uncoated SNPs. Our studies suggested that the capping of nanoparticles by bacterially produced exopolysaccharides serve as the probable mechanism of tolerance.     

Genotoxicity of titanium dioxide (TiO2) nanoparticles at two trophic levels: plant and human lymphocytes

The environmental fate and behaviour of titanium dioxide (TiO(2)) nanoparticles is a rapidly expanding area of research. There is a paucity of information regarding toxic effect of TiO(2) nanoparticles in plants and to certain extent in humans. The present study focuses on the effect of exposure of TiO(2) nanoparticles in two trophic levels, plant and human lymphocytes. The genotoxicity of TiO(2) nanoparticles was evaluated using classical genotoxic endpoints, comet assay and DNA laddering technique. DNA damaging potential of TiO(2) nanoparticles in Allium cepa and Nicotiana tabacum as representative of plant system could be confirmed in the comet assay and DNA laddering experiments. In Allium micronuclei and chromosomal aberrations correlated with the reduction in root growth. We detected increased level of malondialdehyde (MDA) concentration at 4mM (0.9 μM) treatment dose of TiO(2) nanoparticles in Allium cepa. This indicated that lipid peroxidation could be involved as one of the mechanism leading to DNA damage. A comparative study of the cytotoxic and genotoxic potential of TiO(2) nanoparticles and bulk TiO(2) particles in human lymphocytes also reveal interesting results. While TiO(2) nanoparticles were found to be genotoxic at a low dose of 0.25 mM followed by a decrease in extent of DNA damage at higher concentrations; bulk TiO(2) particles reveal a more or less dose dependent effect, genotoxic only at dose 1.25 mM and above. The study thus confirms the genotoxic potential of TiO(2) nanoparticles in both plant and human lymphocytes.     

Examining Environmental Kuznets Curve for river effluents in India

This study aims to determine the trade-off between river pollution and the growth of the economy in the context of India using the concept of Environmental Kuznets Curve (EKC). According to EKC theory, environmental pressure tends to rise faster than income growth in the early stages of economic development and then declines in the later stages with further economic growth. The present study has used the cross-sectional time series data for river pollutants of Biochemical Oxygen Demand (BOD) and Dissolved Hydrogen Ions (PH) across various states of India for the period 1990–1991 to 2005–2006. This study shows why the conventional EKC model is not sufficient to ascertain the declining path of pollution as the economy grows in the second stage. The paper uses the modified EKC theory where the EKC curve is proposed to have 2 turning points. Our results indicated ‘tilted-S shaped’ relationship which contradicts EKC in the early stages. Most of the regions that were studied have crossed the first turning point but are still to cross the second turning point, which means that there will be an ascent in the pollution level in the future. This calls for more stringent environment policies complementing the desired growth path.     

Organochlorine pesticide residues in sediments of a tropical mangrove estuary,India: implications for monitoring

The paper examines the concentrations of isomers of hexachlorocyclohexane (HCHs), dichlorodiphenyl trichloroethane and its metabolites (DDTs), alpha-endosulfan and endosulfan sulfate in surface sediment samples collected from the mouth of Hugli estuary in the vicinity of Sundarban mangrove environment, eastern part of India. An overall pattern of accumulation of these pesticides was in the order of: SigmaHCH>endosulfan sulfate>SigmaDDT>alpha-endosulfan. The concentration of these compounds was quite low. An elevated level of SigmaHCH, SigmaDDT and endosulfan sulfate were marked during premonsoon months, a period characterized by high salinity and pH values. Among the isomers and metabolites of HCH and DDT, beta-HCH, pp'-DDT and pp'-DDE were found to be dominant. The sources of contamination are closely related to human activities, such as domestic and industrial discharges, agricultural chemical applications and soil erosion due to deforestation. The study is compared to other estuarine environment in India and abroad. The present data will serve as a baseline against which future anthropogenic effects may be assessed.     

From Bathymetry to Bioshields: A Review of Post-Tsunami Ecological Research in India and its Implications for Policy

More than half a decade has passed since the December 26th 2004 tsunami hit the Indian coast leaving a trail of ecological, economic and human destruction in its wake. We reviewed the coastal ecological research carried out in India in the light of the tsunami. In addition, we also briefly reviewed the ecological research in other tsunami affected countries in Asia namely Sri Lanka, Indonesia, Thailand and Maldives in order to provide a broader perspective of ecological research after tsunami. A basic search in ISI Web of Knowledge using keywords “tsunami” and “India” resulted in 127 peer reviewed journal articles, of which 39 articles were pertaining to ecological sciences. In comparison, Sri Lanka, Indonesia, Thailand and Maldives had, respectively, eight, four, 21 and two articles pertaining to ecology. In India, bioshields received the major share of scientific interest (14 out of 39) while only one study (each) was dedicated to corals, seagrasses, seaweeds and meiofauna, pointing to the paucity of research attention dedicated to these critical ecosystems. We noted that very few interdisciplinary studies looked at linkages between pure/applied sciences and the social sciences in India. In addition, there appears to be little correlation between the limited research that was done and its influence on policy in India. This review points to gap areas in ecological research in India and highlights the lessons learnt from research in other tsunami-affected countries. It also provides guidance on the links between science and policy that are required for effective coastal zone management.     

Evaluation of environmental fate of acetamiprid in the laboratory

The acetamiprid, a nenicotinoid insecticide, is a popular crop protection agent used in fields as well as in protected cultivation. A laboratory experiment was conditions to study the effect of light, moisture, and pH on the persistence of acetamiprid in water and soil. Dissipation half-lives of acetamiprid in water at pH 4, 7, and 9 were 6.2, 7.3, and 5.1 days, respectively, and 4.3 days under UV and sunlight conditions. Half-life in soil at three concentrations, 0.1, 1.0, and 10 μg g^?1 under different moisture regimes varied from 21.5–22.8, 15.6–22.4, 10.0–15.8 days, respectively, indicating that acetamiprid dissipated faster in submerged soil as compared to field capacity moisture and dry conditions. The leaching study showed that the possibility for leaching of acetamiprid to ground water is extremely low under normal condition of average rainfall due to compact nature soil in the field. Acetamiprid poses low risks to the ecosystem because of their rapid dissipation and low-bound residues in the environment.     

Residual behavior and risk assessment of flubendiamide on tomato at different agro-climatic conditions in India

Supervised field trials were conducted at four different agro-climatic zones in India to evaluate the dissipation pattern and risk assessment of flubendiamide on tomato. Flubendiamide 480 SC was sprayed on tomato at 48 and 96 g active ingredient (a.i.) ha^?1. Samples of tomato fruits were drawn at 0, 1, 3, 5, 7, 10, 15, and 20 days after treatment. Quantification of residues was done on a high-performance liquid chromatography (HPLC) device with a photo diode array detector. The limit of quantification (LOQ) of this method was found to be 0.01 mg kg^?1 while limit of detection (LOD) being 0.003 mg kg^?1. Residues of flubendiamide were found below the determination limit of 0.01 mg kg^?1 in 20 days at both the dosages in all the locations. The half-life of flubendiamide at an application rate of 48 g a.i.?ha^?1 varied from 0.33 to 3.28 days and at 48-g a.i. ranged from 1.21 to 3.00 days. On the basis of data generated under the All India Network Project on Pesticide Residues, a preharvest interval (PHI) of 1 day has been recommended, and the flubendiamide 480 SC has been registered for its use on tomato by the Central Insecticide Board and Registration Committee, Ministry of Agriculture, Government of India. The maximum residue limit (MRL) of flubendiamide on tomato has been fixed by the Ministry of Health and Family Welfare, Government of India under Food Safety Standard Authority of India, as 0.07 μg g^?1 after its risk assessment.     

Radiation induced effects on viability and antioxidant enzymes of crustaceans from different habitats

The paper describes differential tolerance of two fresh water crustaceans Mesocyclops hyalinus and Allodiaptomus satanus to 60Co gamma radiation. Mesocyclops hyalinus is dominant species at site 1, near a Thermal Power Plant at Kolaghat East Midnapore where fly ash deposition is a regular phenomenon. Allodiaptomus satanus is dominant species at site 2 at Kolkata, Ballygung where anthroponotic activities are more pronounced. M. hyalinus is naturally exposed to more stressful situation than A. satanus as revealed by comparing the hydrological parameters of the two habitats. Experimental exposure to ionizing radiation resulted in differential changes in viability morphology and antioxidant enzyme activities in the two selected species. Survival experiments showed greater tolerance of M. hyalinus compared to A. satanus up to 8Gy (absorbed dose) after which if showed drastic fail in survival. More pronounced morphological changes were observed in A. satanus as compared to that in M. hyalinus. The pattern of changes in antioxidant enzyme activity is distinctly opposite in the two radiation exposed species. While in M. hyalinus stimulation in activity of both CAT (excepting at 10Gy absorbed dose) and SOD was observed A. satanus showed decrease in activity of both the enzymes when compared to their unirradiated counterparts.     

Performance study and kinetic modeling of hybrid bioreactor for treatment of bi-substrate mixture of phenol-m-cresol in wastewater: Process optimization with response surface methodology

Performance of a hybrid reactor comprising of trickling filter(TF) and aeration tank(AT) unit was studied for biological treatment of wastewater containing mixture of phenol and m-cresol,using mixed microbial culture.The reactor was operated with hydraulic loading rates(HLR) and phenolics loading rates(PLR) between 0.222-1.078m3/(m2·day) and 0.900-3.456kg/(m3·day),respectively.The efficiency of substrate removal varied between 71%-100% for the range of HLR and PLR studied.The fixed film unit showed better substrate removal efficiency than the aeration tank and was more resistant to substrate inhibition.The kinetic parameters related to both units of the reactor were evaluated and their variation with HLR and PLR were monitored.It revealed the presence of substrate inhibition at high PLR both in TF and AT unit.The biofilm model established the substrate concentration profile within the film by solving differential equation of substrate mass transfer using boundary problem solver tool ’bvp4c’ of MATLAB 7.1 software.Response surface methodology was used to design and optimize the biodegradation process using Design Expert 8 software,where phenol and m-cresol concentrations,residence time were chosen as input variables and percentage of removal was the response.The design of experiment showed that a quadratic model could be fitted best for the present experimental study.Significant interaction of the residence time with the substrate concentrations was observed.The optimized condition for operating the reactor as predicted by the model was 230mg/L of phenol,190mg/L of m-cresol with residence time of 24.82 hr to achieve 99.92% substrate removal.